The Immobilization Of Gluconobacter Oxydans And Assessment Of Cells Activity

Gluconobacter oxydans is famous for its special ability to oxidize various substrates incompletely to corresponding valuable products. Therefore, it is widely used in bio-industrials. In this research, G. oxydans were immobilized in different carriers such as macroporous resin, diatomite, chitosan and its derivatives. Optimize the method and obtain the best goal which promises a potential way to apply in the industry.In the first part, use macroporous resin, diatomite, chitosan and catechol-chitosan to immobilize the cells and assess the cells activities. After immobilization, the immobilized rate was that the macroporous resin and modified resin was62%and83%, the diatomite and modified diatomite was81%and84%, chitosan with glutaraldehyde and catechol-chitosan was100%and64%. The activity recovery of macroporous resin and modified resin was66%and68%, the diatomite and modified diatomite was65%and61%, chitosan with glutaraldehyde and catechol-chitosan was52%and76%. But the bonding force between cells and carriers (macroporous resin, diatomite) was weak, so the cells easily dropped from the carrier. The cells residual rate was50%after stirred3.5h, the cells activity was58%and49%after6batches in catechol-chitosan and chitosan with glutaraldehyde.In order to improve the immobilization rate, embedding method is applied, the porogen is used to enhance the materials’transferring performance.In the second part, I use a novel method to immobilize G. oxydans in the chitosan spongy material which was synthesized using NaHCO3as the porogen, glutaraldehyde as cross-linking agent.Optimize the experiment condition:the mass fraction of chitosan, NaHCO3and glutaraldehyde was1.5%,10%and0.5%.After optimized, the immobilized rate is100%and the activity recovery is92%. The optimal temperature and pH was30℃and6.0. Furthermore, the immobilized cells retained more than70%of its origin activity after12repeated reaction cycles and the free cells only retained50%and there is no cell leakage from the biocarrier after stirred60h.